Multi-staged water manifold system for a water source heat pump

ABSTRACT

One aspect, as provided herein, is directed to a multi-stage fluid control system for a fluid source heat pump system. This embodiment comprises compressors configured to operate as separate, heat exchange stages, condensers each being fluidly coupled to at least one of the compressors by refrigerant tubing and having intake ends coupled together by a fluid intake manifold. This embodiment further includes output conduits coupled to each of the condensers and that are couplable to a distal location. Further included is a modulating valve control system interposed the output conduits. The modulating valve control system is configured to stage a flow of fluid through the condensers based on a number of operating compressors.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based on U.S. Provisional Application, Ser. No.61/539,344, filed on Sep. 26, 2011 and U.S. Provisional Application,Ser. No. 61/538,358, filed on Sep. 26, 2011, both of which areincorporated herein by reference.

TECHNICAL FIELD

This application is directed, in general, to a water source heat pump(WSHP) and, more specifically, to a WSHP having a multi-stage fluiddelivery system.

BACKGROUND

Water source heat pumps are presently used in large commercial orresidential buildings' cooling systems. These WSHP units capture wasteheat from refrigeration-racks and use it to heat stores in winter andreduce peak loading in summer. Also, these systems are very similar tochiller systems that are also well known with the exception that theycan also run in a reverse cycle and function as a heat pump, therebyallowing them to function for both winter and summer heating/coolingapplications. Basically, the unit uses a refrigerating system to cool orheat water, which is used as a heat exchange mechanism to remove or addheat to the system. The water passes through a condensing coil andremoves heat from the refrigerant before passing through the expansionvalve. These units are desirable because they are more efficient inheating and cooling large commercial or residential spaces, thanstandard cooling and heating systems. Though these units are effectivein providing heating and cooling to the building intended to be cooledor heated, they are less efficient than desirable, given present dayconcerns to reduce both power and water use or consumption.

SUMMARY

One embodiment, as provided herein, is directed to a multi-stage fluidcontrol system for a fluid source heat pump system. This embodimentcomprises compressors configured to operate as separate, heat exchangestages, and condensers that are each fluidly coupled to at least onedifferent compressor by refrigerant tubing. The condensers have intakeends that are coupled together by a fluid intake manifold. Thisembodiment further includes output conduits that are coupled to each ofthe condensers and that are couplable to a distal location. Furtherincluded is a modulating valve control system interposed the outputconduits. The modulating valve control system is configured to stage aflow of fluid through the condensers based on a number of operatingcompressors.

Another aspect is direct to a different embodiment of a multi-stagewater control system for a water source heat pump. This embodimentcomprises compressors that are fluidly coupled to one or moreevaporators and condenser units having intake ends that are fluidlycoupled together by a manifold. Each of the condenser units are fluidlycoupled to a different one of the compressors by refrigerant tubing toform multiple, separate refrigeration loops. This embodiment furtherincludes a water intake conduit coupled to the manifold and outputconduits coupled to each of the condenser units. Each of the outputconduits has a water control valve interposed therein. A controller iscoupled to the water control valves and is configured to control thewater control valves to stage a flow of water through the condensersbased on a number of the compressors that are operating.

Another embodiment is directed to a method of manufacturing amulti-stage fluid control system for a fluid source heat pump system.This embodiment comprises placing compressors on a housing frame thatare configured to operate as separate, heat exchange stages, placingcondensers on the housing frame and fluidly coupling each of them to atleast one of the compressors by refrigerant tubing. The condensers haveintake ends that are coupled together by a fluid intake manifold. Themethod further comprises coupling output conduits to each of thecondensers that are couplable to a distal location, and interposing amodulating valve control system in the output conduits. The modulatingvalve control system is configured to stage a flow of fluid through thecondensers based on a number of operating compressors.

BRIEF DESCRIPTION

Reference is now made to the following descriptions taken in conjunctionwith the accompanying drawings, in which:

FIG. 1 illustrates a schematic diagram showing the multi-stageconfiguration of the heat pump system as provided herein;

FIG. 2 illustrates a perspective view of one embodiment of a WSHPaccording to FIG. 1;

FIG. 3 illustrates a perspective view of one embodiment of the fluidcontrol system associated with the WSHP of FIG. 2.

DETAILED DESCRIPTION

FIG. 1 illustrates a schematic diagram of a multi-stage fluid controlsystem for a fluid WSHP unit 100 as covered by the embodiments discussedherein and which can be used in conjunction with a conventional roof topunit (RTU). For purposes of understanding this disclosure and claims, itshould be understood that the term “refrigerant” pertains to therefrigerant fluid flowing through the compressors 105, 110 and “fluid”pertains to any heat exchange fluid flowing through the condensers 115,120. This particular embodiment comprises compressor 105, 110 that areconfigured to operate in separate, heat exchange stages. The compressors105, 110, may be of conventional design and are operated in separatecycles, or when more than two compressors are present, multiplecompressors may be operated at the same time. For example, if fourcompressors are present, two compressors may be operated together in afirst operation cycle or stage, and the remaining two compressors may beoperated together in a second operation cycle or stage. Alternatively,the four compressors may operate in separate, first, second, third andfourth stages. As used herein and in the claims, “stage” means arefrigerant cycle operation where the compressor is operating andrefrigerant is passing through the associated condenser, and heatexchange is occurring between the refrigerant flowing through thecompressors 105, 110 and the fluid, such as water, glycol, or some otherknown heat exchanging fluid, passing through the condensers 115 or 120.

Condensers 115, 120 are each fluidly coupled to least one differentcompressor 105 or 110 by refrigerant tubing 112, 114, to form separaterefrigerant cycles with the compressor to which the condenser 115, 120is coupled. In certain embodiments, each of the condensers 115, 120 iscoupled to a different compressor 105, 110, however, in otherembodiments, one of the condensers 115, 120 may be coupled to more thanone compressor. The condensers 115, 120 have intake ends coupledtogether by a fluid intake manifold 125. The manifold 125 is common tothe condensers 115, 120 and provides fluid flow into the condensers 115,120. Also the condensers 115, 120 may be of conventional design, such asconcentric coil condensers, as those illustrated herein, or they may bea conventional brazed-plate condenser. The condensers 115, 120 aredesigned to have separate refrigerant and fluid paths through which heatexchange occurs. Moreover, it should be understood that while only twocompressors and two condensers are shown, the present disclosure is notlimited to this particular numerical design and is expandable toaccommodate different heat/cooling needs of a given structure.

This embodiment further includes output conduits 130, 135, respectively,coupled to each of the condensers 115, 120. The output conduits 130, 135are couplable to a distal location, which is a location outside the heatpump system 100, such as a user's building or cooling tower or RTU. Theoutput conduits 130, 135 can be joined together downstream from thecondensers 115, 120 to provide a common conduit to the distal location,as shown. Further included, is a modulating valve control system 140interposed the output conduits 130, 135. The modulating valve controlsystem comprises separate modulating valves 140 a, 140 b that areinterposed the conduits 130, 135 of the respective condensers 115, 120with which it is associated. Modulating valves 140 a, 140 b are capableof proportionally controlling water by going from fully open to fullyclosed; or by going from a water flow setpoint determined by a RTU unitcontroller to a closed position (no water flow) determined by the RTUcontroller. Water setpoint is a flow in gallons per minute(GPM) or on atemperature drop (Delta T) through the water cooled condenser. Thisvalue can either be factory set or field/customer configurable. Thisrepresents a significant cost savings by not having to have dedicatedautomatic temperature controllers (ATC's) or automatic temperature/flowcontrols on each water/refrigerant stage in addition to the motorizedon/off shut off valve. Additionally, as explained below, in otherembodiments, the modulating valve control system 140 may also include acontroller that can comprise one or more microprocessors. The modulatingvalve control system 140 is configured to control a flow of fluidthrough the condensers 115 or 120, based on the required operation ofthe compressor 105 or 110 to which the condenser 115 or 120 isrespectively coupled.

For example, in a stage 1 heat exchange cycle and just before thecompressor 105 is activated, a signal goes out to the modulating valvecontrol system 140, which causes the valve 140 a to open. This allows aflow of fluid to begin flowing through condenser 115 for a short periodof time and charge the condenser 115 with fluid. Following this briefperiod of time, compressor 105 is then activated. During stage 1 , valve140 b remains in the closed position, as long as there is not a need toactivate compressor 110 with which condenser 120 is associated, therebypreventing a flow of fluid through condenser 120. However, if there is acall from a controller for stage 2 operation, a signal goes out to themodulating valve control system 140, which causes the valve 140 b toopen, just prior to the activation of compressor 110, which allowscondenser 120 to be charged with fluid. The opening of the valve 140 ballows a flow of fluid through condenser 120 during the operation ofcompressor 110. Thus, where there is only a need for stage 1 operation,fluid is flowing only through the condenser 115, which is associatedwith compressor 105. Alternatively, when there is a need for both stage1 and stage 2 operation, fluid is flowing through both of the condenser115, 120 during the operation of compressors 105, 110.

In view of the above, fluid flow through the condensers 115, 120 iscontrolled by the valve control system 140 in such a way that only thefluid that is needed to meet heating/cooling requirements is pumpedthrough the condenser associated with the operating compressor. This isin stark contrast to conventional, single stage systems where fluidflows through each condenser regardless of which compressor stage isoperating. In such conventional systems, no staged multiple valvecontrols are present, so fluid is flowing through all the condenserswhen any one of the compressors is operating. As such, there is nostaging of fluid flow through the condensers with the operation of thecompressors. As a result, all of the fluid pumps run at all times duringthe operation to maintain the required pump pressure within the system.This constant pump operation requires more pump energy than theembodiments provided by this disclosure.

In operation, fluid, such as water from a distal location, is pumpedtoward the WSHP unit 100. In a cooling operation mode, the refrigerantwithin each refrigeration circuit leaves the associated compressor as ahot gas. When the hot refrigerant gas passes through the refrigerantpath within condensers 115 or 120, it transfers heat to the fluid thatflows through a fluid path within the condensers 115 or 120. Therefrigerant becomes cooler and turns to a liquid state before passingthrough an expansion vale, not shown, after which it quickly expandsinto a cold gas as it passes through an evaporator or indoor coil asseen in FIG. 2, as described below. Of course, in a heating mode, theabove described cycle is reversed to provide heat to the indoor coils.

As noted above each stage 1 (compressor 105 and condenser 115) and stage2 (compressor 110 and condenser 120) has separate modulating controlvalves 140 a and 140 b associated with them. As such, these modulatingcontrol valves 140 a and 140 b control the fluid through the condensers115, 120 in a staged manner, such that only the condensers associatedwith active refrigeration circuits have refrigerant and fluid passingthrough them. Moreover, modulating control valves 140 a and 140 b can bespecifically designed to include a motorized actuator, automatic flowcontrol, and 3-way valves (for by-pass). In such embodiments, themotorized actuators are opened when the respective compressors areenergized with T-stat demand signals Y1, Y2, . . . and W1, W2 . . . ,etc. The condensers 115, 120, which are, in certain embodiments,arranged in a parallel arrangement, are coupled together by the manifold125 so that fluid is able to flow though only the condenser that has anactive refrigeration circuit. Thus, a matching in refrigerant flow withfluid flow can be achieved, and only fluid that is doing the work willbe pumped at any given point in time. Moreover, these systems canprovide a variable flow rate and allow the flow rate to be staged tocoincide with the number of active compressors within the system at anygiven point in time, which provides significant pump volume and energysavings. The flow rate is reduced and that in turn has a significantimpact to the pump horse power, which results in energy savings.

With the present disclosure, it has been found that staging the fluidthrough the condensers 115, 120 provides a system that saves energy, byreducing the fluid required to run the pumps by up to about 50% in partload conditions in a two compressor system. This translates to about 86%savings in pump energy, when using a typical speed controlledcentrifugal pump water system. Moreover, in a four compressor system,flow rate reduction can be increased further, even up to about 75%,which can translate into as much as about 97% savings in pump energy,when using a typical centrifugal pump water system. As such, this uniqueconfiguration allows not only a reduction of fluid flow but asignificant pump energy savings over conventionally designed systems.

FIG. 2 illustrates one configuration of the WSHP system 100, asgenerally discussed above. In this embodiment, a WSHP unit 200 includesa housing frame 202 on which the various components of the WSHP system200 are placed, and the condensers mentioned above regarding FIG. 1 arewater condenser coils 204, 206, wherein each of the condenser coils 204,206 includes two coils. The condenser coils 204, 206 may be ofconventional design with each of the dual coils comprising twoconcentric tubes that form a separate refrigerant path and fluid pathwithin them. As shown, condenser coil 204 is coupled to compressor 208by refrigerant tubing 210 to form a first refrigerant cycle, or stage 1,and condenser coil 206 is coupled to compressor 212 by refrigeranttubing 214 to form a second refrigerant cycle, or stage 2. Though onlytwo compressors and two coils are shown, it should be understood thatthe system can be expanded to include multiple coils and compressors ina 1:1 coil/compressor ratio. As such, the system can easily be expandedfor increased capacity as design requires.

The two above-mentioned stages share a common intake water manifold, notshown in this view that is located at the bottom of the condensing coils204 and 206 and supplies water to both coils. The first and second stagecondensing coils 204, 206 form separate fluid paths and the water,though taken in through the common manifold, is not intermixed once thefluid enters each of the stage 1 and stage 2 coils 204, 206. The stage 1and stage 2 condensing coils 204, 206 are comprised of concentric tubesin which the most center tube forms the water path and the outer, largerconcentric tube forms the refrigerant path. The temperature differencebetween the refrigerant and water flowing through the concentric tubesallows for the heat exchange to occur. The operations of the WSHP unit200, as described herein, are controlled by an unit controller 216 andcan include the programming and one or more microprocessors andmicrocircuits boards necessary to implement the embodiment describedherein.

Compressors 208 and 212 are fluidly connected to an indoor evaporatorcoil 218 through which air is directed by a motor 220 and fan 222through filter 224 and an optional economizer damper 226. Theillustrated embodiment also includes a conventional first chargecompensator 228 associated with compressor 208 and a conventional secondcharge compensator 230 associated with compressor 212. The compressors208 and 212 also have first and second reverse valves 232, respectivelyassociated therewith to allow the refrigerant flow direction, andsubsequently the refrigeration cycle in the unit to be operated inreverse. The unit 200 further includes the valve control system 234,conduit system 236, including water input and outputs 238, 240, whichare explained in more detail below.

FIG. 3 is a partial view of the WSHP unit 200 of FIG. 2 that illustratesthe condensers, conduits, and valve control system 300 of the WHSP unit200. In this embodiment the system 300 has a two stage quad condensingcoil configuration wherein each stage includes two condensing coils 302,304. This embodiment further illustrates a common water inlet point 306that is couplable to a water source from a distal use point, such as auser's structure or cooling tower. The water can pass through athree-way valve 308 that is positioned in a by-pass position 310 or amain loop position 312. The three-way valve 308 is connected to astrainer 314 that moves foreign debris from the water flowing throughthe system 300. Conduit pipe 316 leads from the strainer 314 to amanifold 318 that feeds both the condensing coils 302, 304. The stage 2coil 302 is connected by a conduit 320, on its outlet side, to a stage 2flow control valve 322, and the stage 1 coil 304 is connected by conduit324, on its outlet side, to a stage 1 flow control valve 326, as shown.The separate outlet conduits 320 and 324 and control valves 322 and 326allow for a staging of the water flow through the WSHP system 200 ofFIG. 2, as explained above. Once the water passes through either one orboth of the control valves, it first passes through automatic flowregulator and air event sections 328, 330, after which, conduits 320 and324 merge into a single conduit 332. The water then passes throughthree-way valve 334 and to the distal point of use, provided thethree-way valve 334 is in a main loop position 336. However, if thethree-way valve 306, 334 is in the by-pass position 310, 338, the watertravels through the flexible hose 340 and back out of the unit,by-passing the condensers, conduits and valve control systems. By-passmode provides advantages during water system commissioning and start up,by allowing external water-loop connections in the building to pressurechecked, flushed and drained without exposing any of the flow controland condenser heat exchanger to potentially damaging high-air pressures.It's common practice to use high pressure and non chemically treatedwater to flush contaminants from the building water loop piping systemsduring the startup process. If the WSHP is left connected during theflushing process there is the potential to expose the WSHP to a highconcentration of contaminants and cleaners could potentially damage thecopper and brass materials that are commonly used in water cooledcondenser flow control and heat transfer systems. Another advantage ofhaving a flow-control system w/a built-in bypass mode is the ability torepair and/or replace systems down-stream of the main water loop w/ohaving to disconnect the connection points between the buildings's mainwater loop and the RTU.

The foregoing presents embodiments of an improved WSHP that allowsstaging of the condensers in tandem with only the compressors that areoperating. This reduces pump energy in that pump pressure is reduced andallows significant savings in energy costs and water consumption in theoperation of the WSHP unit. Moreover, this savings in pump energy,derived from restricting fluid flow to non-active condenser circuitsdoes not impact the operations efficiency of the refrigeration system.

Those skilled in the art to which this application relates willappreciate that other and further additions, deletions, substitutionsand modifications may be made to the described embodiments.

What is claimed is:
 1. A multi-stage fluid control system for a fluidsource heat pump system, comprising: compressors configured to operateas separate, heat exchange stages; condensers each being fluidly coupledto at least one different of said compressors by refrigerant tubing andhaving intake ends coupled together by a fluid intake manifold; outputconduits coupled to each of said condensers and being couplable to adistal location; and a modulating valve control system interposed saidoutput conduits, said modulating valve control system configured tostage a flow of fluid through said condensers based on a number ofoperating compressors.
 2. The system recited in claim 1, wherein saidcompressors comprise two or more compressors.
 3. The system recited inclaim 2, wherein said condensers comprise two or more condensers,wherein each of said condensers is fluidly coupled to a different one ofsaid compressors by said refrigerant tubing to form separaterefrigeration loops.
 4. The system recited in claim 1, wherein saidmodulating valve control system comprises a first modulating valveinterposed a first conduit coupled to a first of said condensers and asecond modulating valve interposed a second conduit coupled to a secondof said condensers.
 5. The system recited in claim 4, wherein saidmodulating valve control system further includes a control systemcoupled to said first and second modulating valves, said control systembeing configured to stage a flow of fluid through said first and secondcondensers based on said number of operating compressors.
 6. The systemrecited in claim 5, wherein said modulating valve control systemincludes one or more microcontrollers for controlling said first andsecond modulating valves.
 7. The system recited in claim 5, wherein saidmodulating valve control system is configured to open said first valvefor fluid flow to said first condenser only when a first of saidcompressors is operating and to open said second valve for a fluid flowto said second condenser only when a second of said compressors isoperating.
 8. The system recited in claim 1, further comprising anintake conduit coupled to said manifold, said intake conduit configuredto be couplable to said distal location.
 9. A multi-stage water controlsystem for a water source heat pump, comprising: compressors fluidlycoupled to one or more evaporators; condenser units having intake endsthat are fluidly coupled together by a manifold, each of said condenserunits being fluidly coupled to a different one of said compressors byrefrigerant tubing to form multiple, separate refrigeration loops; awater intake conduit coupled to said manifold; output conduits coupledto each of said condenser units, each of said output conduits having awater control valve interposed therein; and a controller coupled to saidwater control valves and configured to control said water control valvesto stage a flow of water through said condensers based on a number ofsaid compressors that are operating.
 10. The system recited in claim 9,wherein said compressors comprise two or more compressors.
 11. Thesystem recited in claim 9, wherein a first of said water control valvesis interposed a first of said output conduits coupled to a first of saidcondenser units and a second of said water control valves is interposeda second of said output conduits coupled to a second of said condenserunits.
 12. The system recited in claim 11, wherein said controller isconfigured to control said first and second water control valves tostage a flow of water through one or both of said first and secondcondensers based on said number of said operating compressors.
 13. Thesystem recited in claim 12, wherein said controller includes one or moremicrocontrollers for controlling said first and second water controlvalves.
 14. The system recited in claim 12, wherein said controller isconfigured to open said first water control valve for fluid flow to saidfirst condenser only when a first of said compressors is operating andto open said second water control valve for a fluid flow to said secondcondenser only when a second of said compressors is operating.
 15. Thesystem recited in claim 9, further comprising an intake conduit coupledto said manifold, said intake conduit configured to be couplable to adistal location.
 16. A method of manufacturing a multi-stage fluidcontrol system for a fluid source heat pump system, comprising: placingcompressors on a housing frame, said compressors being configured tooperate as separate, heat exchange stages; placing condensers on saidhousing frame and fluidly coupling each to at least one of saidcompressors by refrigerant tubing, said condensers having intake endscoupled together by a fluid intake manifold; coupling output conduits toeach of said condensers, said output conduits being couplable to adistal location; and interposing a modulating valve control system insaid output conduits, said modulating valve control system configured tostage a flow of fluid through said condensers based on a number ofoperating compressors.
 17. The method recited in claim 16, whereinplacing said compressors comprises placing two or more compressors onsaid housing frame and placing said condensers comprises placing two ormore condensers on said housing frame and fluidly coupling each of saidcondensers to a different one of said compressors by said refrigeranttubing to form separate refrigeration loops.
 18. The method recited inclaim 16, wherein interposing said modulating valve control systemcomprises interposing a first modulating valve in a first conduitcoupled to a first of said condensers and interposing a secondmodulating valve in a second conduit coupled to a second of saidcondensers.
 19. The method recited in claim 18, wherein said modulatingvalve control system further includes a control system coupled to saidfirst and second modulating valves and comprising one or moremicroprocessors, said control system being configured to stage a flow offluid through said first and second condensers based on said number ofoperating compressors.
 20. The method recited in claim 18, wherein saidcontrol system is configured to open said first valve for fluid flow tosaid first condenser only when a first of said compressors is operatingand to open said second valve for a fluid flow to said second condenseronly when a second of said compressors is operating.